1. Field of the Invention
The present invention relates in general to framing an automotive vehicle, and, more specifically, to a method of framing structural members to an underbody of an automotive vehicle.
2. Description of the Related Art
One typical type of vehicle frame assembly is made from a plurality of structural members. The structural members are held in juxtaposition by temporarily affixing or loosely clamping them together at a first framing workstation. The temporarily affixed or clamped structural members are then moved to a second workstation where the structural members are specifically positioned relative to one another by a variety of fixtures and the structural members are secured to one another by a plurality of spot welds. The spot welded structure is moved to a third framing station where the clamps are removed and another welding operation is performed to permanently secure all of the structural members together to form a single vehicle frame. Alternative framing operations include providing a first set of structural members (e.g., underbody) at a first workstation. A second set of structural members (e.g., body sides) are assembled to the underbody. The underbody and the second set of structural members are moved to a second workstation where a third set of structural members such a roof frames and roofing cross members are assembled. The assembled structural members is then moved to a fourth workstation where additional inner framing structures may be added for assembly. The assembled structural members are then moved to a fifth workstation where all framing joints are then permanently welded. These common types of framing and assembly operations utilize numerous manufacturing operations, added equipment at the various workstation locations, and added manufacturing space to perform the numerous framing and assembly operations.
Vehicle frames require high strength framing for various purposes which include stability, reliability, crashworthiness, low NVH, and riding comfort. Manufacturers of vehicles are constantly redesigning vehicle frames to reduce the overall weight of the vehicle for increasing fuel economy while maintaining the high strength features of the vehicle frame. Furthermore, it is desired that the cost of manufacturing the vehicle frames be kept low by manufacturing the framing assemblies with few operations and minimal specialized equipment.
Aluminum frame components have been used as substitutes for steel framing parts. Aluminum components in certain designs can lower the cost and weight of the vehicle frame while maintaining required features such as high strength and reliability. However, substitution of aluminum has not been completely successful. For example, aluminum has anodic properties which when combined with another metal or alloy having high cathodic properties may accelerate the corrosion of the aluminum. Combining aluminum with non-aluminum components close to its anodic index (such as steel) reduces the effects of galvanic corrosion and creates advantages such as higher strength, improved NVH, lower weight, and lower cost. However, manufacturing of such composites structures has resulted in numerous and complex manufacturing operations including multiple workstations and excessive measures to ensure sufficient assembly and joint strength between aluminum components and other components.